Apparatus for controlling highway crossing signals



Aug. 21, 1956 R. R. KEMMERER APPARATUS FOR CONTROLLING HIGHWAY CROSSINGSIGNALS Filed July 25, 1952 w. L. Std:

H15- dTFOEVEY Nww m. NEH v M mm a g Rm EN u d ..........il.ii -1 wkTlwuS m I QSQ w w m .R Ql

United States Patent APPARATUS FOR CONTROLLING HIGHWAY CROSSING SIGNALSRalph R. Kemmerer, Swissvale, Pa., assignor to Westinghouse Air BrakeCompany, Wilmerding, Pa., acorporation of Pennsylvania Ap plication July23, 1952, Serial No. 300,563

9 Claims. (Cl. 246 130) My invention relates to apparatus forcontrolling highway crossing signals, and particularly to apparatus" forprotecting against momentary losses of track circuit shunt in highwaycrossing signal control systems whichv embody an energy storing device,such for example as a capacitor, for delaying the starting of theoperation of a highway crossing signal when a train approaches within agiven distance of the intersection of a highway with a railway track.

It is important that a highway crossing signal be operated long enoughbefore the arrival of a train at. the intersection of a highway with arailway track, to provide ample warning to users of the highway that atrain is approaching, so that users of the highway will have sufiicienttime to get into the clear. It is, however, desirable that a highwaycrossing signal be not operated so long before the arrival of a train atthe intersection as to unduly delay users of the highway and therebycause them to become careless about obeying the'indications given byhighway crossing signals.

It is well-known practice to install insulated joints for dividing arailway track into approach and crossing track sections adjacent anintersection of a highway with a. railway track, for starting theoperation of a highway crossing signal in response to the arrival of atrain within a given distance of the highway crossing, and forcontinuing the operation of the highway crossing signal while the trainis moving over the crossing. If train movements are in both directionsover the track, an approach control section is provided in eachdirection from the intersection. Operation of a highway crossing signalis started when a train approaching an intersection enters the coricetary loss ,of track circuit shunt, and delay still further the startingof the operation of the highway crossing signal If the momentary loss ofshunt of the track circuit for an approach track section should occurnear the end of the delay period normally provided by thecapacitor-resistor arrangement, the resulting delay period might bealmost double the normal delay period intended,

so that the highway crossing signal would provide very little, if any,warning of the approach of a train before the train arrived on thecrossing track section.

In a highway crossing signal control system in which acapacitor-resistor arrangement is employed for delaying the starting ofoperation of a highway crossing signal when a train enters an approachcontrol track section, and which includes means for protecting against amomentary Ios of shunt of the track circuit for the approach controlsection, it is desirable to also avoid excessive operation of a highwaycrossing signal when a second train approaching the'crossing follows afirst train closely. I

' An object of my invention in apparatus for controlling highwaycrossing signals, in which an energy storing device is employed fordelaying the starting of operation of a highway crossing signal when atrain enters an approach control track section, is therefore theprovision of an arrangement for protecting against a momentary loss ofshunt of a track circuit for an approach control section, whichincludes'means for avoiding excessive operaresponding approach controlsection, and is continued until the train vacates the crossing tracksection.

From the standpoint of maintenance costs of insulated track joints, aswell as of the original cost of installing them, it is desirable to keepfrom dividing a railway track into any more sections than can beavoided. If, for some other purpose, such, for example, as the controlof a rail way signal, insulated joints are already installed in arailway track in the vicinity of an intersection of a. highway with therailway track, but at a location. which is farther from the intersectionor crossing than is necessary for providing ample warning to users ofthe highway when a train is approaching the intersection, acapacitor-resistor arrangement can be used for delaying the starting ofthe operation of a highway crossing signal for a desired period of timeafter the leading end of a train approach- I an approach control tracksection, there may be a dangerous condition if there should be amomentaryloss of track circuit shunt of the approach control tracksection. This is because the capacitor in the capacitor-resistor arrangement may become recharged because of a momention of the highwaycrossing signal when a second train approaching the crossing follows afirst train closely.

. A feature of my invention, for accomplishing this object, is theprovision of an approach stick relay ASR having pickup circuitscontrolled by a front contact of a track relay, designated 'by thereference character ITR, for an approach control section, designatedbythe reference character IT, and with a first one of the pickupcircuits controlled to be closed only upon the lapse of a measuredperiod of time in the event of a momentary loss of shunt of the approachcontrol section IT, and with asecond pickup circuit controlled to beclosed promptly when the approach control section 1T becomes vacated bya train which has moved over section 1T while approaching the crossing.

, Another object of my invention is the provision of means forenergizing the approach stick relay ASR promptly when a train movingaway from the associated highway crossing vacates the approach controlsection 1T.

. A feature of my invention for accomplishing this object is theprovision of a third pickup circuit for the approach stick relay ASRcontrolled by a corresponding directional stick relay, designated by thereference character 2WS.

I shall describe one form of apparatus embodying my invention, and shallthen point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view showing one form ofapparatus embodying my invention in which a railway track which isintersected by a highway, designated by the reference character H, isdivided to form a crossing track section, designated by the referencecharacter XT, at the highway, and a first and a second approach controltrack section, designated by the reference characters IT and 2T,respectively, adjacent the opposite ends of the crossing track sectionXT; in which an approach stick relay, designated by the referencecharacter ASR, has three pickup circuits and a stick circuit; in which arepeater relay, designated by the reference character ASPR, iscontrolled by a front contact of relay ASR, and is'made slow releasingby a capacitor t and a resistor r connected in series with each other ina path which is in multiple with the winding of the repeater relay ASPR;in which a timing stick relay, designated by the reference characterTSR, is controlled by a circuit including back contacts of relays ASRand ASPR, and of a time element device TE; in which time element deviceTE is controlled by a front contact of relay TSR; in which a first and asecond control stick relay, designated by the reference characters 1G8and 2C5, respectively, are of the slow pickup type; in which a first anda second or eastbound and westbound directional stick relays, designatedby the reference characters IE8 and 2W5, respectively, are of the slowrelease type; and in which a highway crossing signal control relay,designated by the reference character XR, is controlled by circuit meansincluding contacts of the control stick relays, the directional stickrelays, the repeater relay, and the track relay for the crossing tracksection.

Similar reference characters refer to similar parts in the drawing. A

Referring further to the drawing, a highwaycrossing signal, designatedby the reference character XS, which may be of any suitable design butwhich, as shown in the drawing, is of the flashing light type, islocated adjacent the intersection of the highway H with the railwaytrack.

I shall assume that train movements over the stretch of track from leftto right, as shown in the drawing, are in the eastbound direction, andthat therefore train movements in the opposite direction, from right toleft, are in the westbound direction.

The rails of the railway track are divided by insulated joints 3 to formthe crossing section XT at the intersection of the highway with therailway track, the first or eastbound approach control section 1T,adjacent the west end of section XT, and the second or westboundapproach control section 2T, adjacent the opposite or east end ofsection XT.

Each of the track sections 1T, XT and 2T is provided with a trackcircuit which includes a suitable source of current, such as a battery4, connected across the rails adjacent one end of the section, and atrack relay, designated by the reference character R preceded by therefer ence character for the corresponding section, connected across therails adjacent the opposite end of the section.

The approach stick relay ASR has three pickup circuits and a stickcircuit, each of which includes a front contact 5 of track relay 1TR forthe first or east-bound approach control track section IT. A first oneof the pickup circuits and a second one of the pickup circuits alsoincludes a front contact 8 of relay TSR. The first one of the pickupcircuits also includes a contact 9 of time element device TE. The secondpickup circuit for relay ASR also includes front contact 10 of relay IE8and back contact 11 of relay XTR. The thirdpickup circuit for relay ASRincludes'a front contact 13 of relay 2WS.

Relay TSR has a pickup and a stick circuit, each of whichincludescontact 5 of relay lTR and the back point of contact 7 of relayASR, and the pickup circuit also iiicludes back contacts 35 and 36 ofrelay ASPR and the time element device TE, respectively.

Contact 9 of time element device TE becomes closed when the controlelement 39 of time element devi'c'e TE has been energized for a measuredperiod of time, and back contact 36- becomes closed'upon the lapse of afur- 4 contact 33 of relay 2WS. The pickup circuit for relay 2W5 also"similarly includes the back point of contact 32 of relay 2CS, the frontpoint of contact 30 of relay 1C5, and the back contact 40 of relay lES.Each of the relays lES and 2WS is controlled by its pickup circuit tobecome energized when a train moving in the corresponding directionenters the crossing track section XT.

The crossing signal control relay XR is controlled by front contacts ofthe control stick relays 1G8 and 2CS, the directional stick relays IESand 2WS, repeater relay ASPR, and track rela XTR. Relay XR is normallyenergized.

A flasher control relay, designated by the reference character PR, iscontrolledby a'= back contact 27 of relay XR, and isnormallydeenergized. Relay PR is of the wellknown type having a movablecontact element 29 which, while relay FR is energized, oscillatesbetween a first position, in which it engages a fixed contact element b,and a second position, in which engages a second fixed contact elementa'.

As shown in the drawing, highway crossing signal XS comprises two lamps1e and 22, the lighting circuits for which include contacts 29a and 29b,respectively, of relay PR, and a back contact 28 of relay XR. Lamps 1eand 2', on account of being controlled by contact 28 of relay XR, arenot lighted until relay XR becomes deenergized, causing its contact 27to be closed in a circuit for energizingrelay'FR, and causing itscontact 28 to become closed in the lighting circuits for signal XS.Lamps 1e and 2e of signal XS will thendisplay aflashi-ng indication, onaccount of being repeatedly lighted, alternately, through contacts 291aand 2%, respectively, of relay PR.

The various control and lighting circuits may be energized by I currentfrom any suitable source such, for example, as a battery Q shown in thedrawing, having terminals B and N.

Having described, in general, the arrangement and control' of theapparatus shown by the accompanying drawing, I shall now describe, indetail, its operation.

Asshown in the drawing, all parts of the apparatus are in the normalcondition, that is, each of the track sections is unoccupied, andtherefore track relays llTR, XTR and 2TR are energized; relays ASR,ASPR, 1C8, 2C3 and XK are also energized; and relays 1E5, ZVvS, TSR andFR, time element device TE, and signal XS are deenergi'zed. 1 The threepickup circuits for relay ASR are normally open, but relay ASR isenergized by its stick circuit passing from terminal B, througlr contact5 of relay 1TR, conductor'6, front point ofcontact 7 of relay ASR, andthe" winding of relay ASR to terminal N.

Relay ASPR- is energizedby it's circuit passing from terminal? B,through contact M of relay A-SR, and a resister r in'- series-with acapacitor t in a path in multiple ther period of time after the controlelement 39 has bei 2CS includes a front contact 18 of relay 2TR, and thepick- I up circuit also includes a contact 19 of relay XTR. Each of thedirectional stick relays IE8 and- 2W8 has a pickup and a first stickcircuit which include a back contact 31 of relay XTR. The pickup circuitfor'rclay lES also includes the back point of contact 30 of relay 1C8,the front point of contact 32 of relay ZCS, and back with thewinding ofrelay A-SPR, to terminal N.

Both the pickup circuit and the stick circuit for relay 108 are closed".7 The pickup circuit for this relay passes from terminal B, throughcontacts 1.5 and 16 of relays ASR' and XTR, respectively, and thewinding of relay ICS to terminal The stick circuit is the same as thepickup circuit except that it includes contact 17 of relay 1C5 insteadof contact 16 of relay Both a pickup circuit and a stick circuit arealso" closed for relay 208, the pickup circuit for relay 2C8 passingfrom" terminate, through contacts 18 and 19 of relays ZTR and XTR,respectively, and the winding of relay ZCSY to terminal N. The stickcircuit for relay 2CS is the same as the pickup circuit just tracedexcept that it includes contact 20 of relay 2C8 instead of contact'19 ofrelay p he circuit by which relay XR- is energized passes from terminalB, through contacts 22 and 2,3 of relays 2C5 andXTR, respectively,contact 24 of relay ASPR in multiple with contact 25 of relay ICS, andthe windingof relay to terminal N, v

flSsl me that, with apparatus embodying my ingreases vention arranged asshown in the drawing, an eastbound train enters section 1T, deenergizing"relay lTR. The stick circuit traced for relt y ASR will therefore beopened at contact 5 of relay ilTR, causing relay ASR to be cleenergized.Front contacts 14 and 15 of relay ASR will therefore in turn be openedand contact 7 of relay ASR will become opened at its front point andclosed at its back point. With contact if; of relay ASR open, the pickupand stick circuits traced for relayv ICS willbecorne opened, andtherefore relay 1C8 will become deenergized. With contact 14 of relayASR open,'the energizing circuit for relay ASPR will be opened, butrelay ASPR will be slow to release because of the path through resistorr and capacitor t in multiple with the winding of relay ASPR, andtherefore, although contact of relay ICS is open, the circuit'for relayXR will temporarily remain closed through contact 24 of relay ASPR, sothat relay XR will remain energized for a brief period of time after theeastbound train enters section 1T. i

By the time that contact 24 of relay ASPR opens, the

train will have arrived at a location designated on the drawing as theStarting Point. The distance ofthis starting point from the entering endof section 1T will of course vary for different trains according totheir speed,

so that the higher the speed of the train, the farther the highestspeed, the starting point will be far enough from the intersection forsignal XS to provide ample warning to users of the highway.

When contact 24 of relay ASPR opens, relay XR will become deenergized,since contact 25 of relay ICS is already open. With relay XRdeenergized, relay FR will be energized by a circuit passing fromterminal B, through contact 27 of relay XR, and the winding of relay PRto terminal N. Relay FR, upon thus becoming energized, will oscillateits movable contact element 29 to repeatedly engage alternately thefixed contact elements a and b. With relay XR deenergized, and with themovable contact element 29 engaging the fixed contact element b, lamp 2eof signal XS will be lighted by a circuit passing from terminal B,through contact 28 of relay XR, contact 2% of relay PR, and lamp 2e toterminal N. When movable contact element 29 engages the fixed contactelement a, lamp 1e of signal XS will be lighted by a similar circuitpassing from terminal B, through contact 28 of relay XR, contact 29a ofrelay PR, and lamp le to terminal N.

When the train enters section XT, deenergizing relay XTR, contact 16 ofrelay XTR will become opened in the pickup circuit for relay 1C8, whichis, however, already deenergized onaccount of contact 15 of relay ASRbeing open. Contact 23 of relay XTR will also be opened in the circuittraced for relay XR, which is, however, already deenergized on accountof contacts 24 and 25 of relays ASPR and 1C5, respectively, being open.When back contact 31 of relay XTR becomes closed, the first, oreastbound, directional stick relay lES will become energized by a pickupcircuit passing from terminal. B, through the back point of contact 30of relay 1CS, contact 31 of relay XTR,'front point of contact 32 ofrelay 2C8, contact 33 of relay 2W8, and the Winding of relay 1E8 toterminal N. Relay 1E8, upon becoming energized by its pickup circuit,will complete a first stick circuit passing from terminal B, through theback point of contact 30 of relay 1C8, contact 31 of relay XTR, contact34 of relay IE8, and the winding of relay 1E5 to terminal N. When thetrain enters section 2T, contact 18 of relay 2T R will become opened inthe pickup and stick circuits traced for relay 2C5, causing relay ZCS tobe deenergized. A second stick circuit for relay lES will thereby becom- .pleted, passing; from terminal B, through the back point ofcontact 32 ofrelay ZCS, contact 34 of relay IE8, and the winding ofrelay 1E5 to terminal N.

When the train leaves section 1T, relay TSR will become energized by itspickup circuit passing from terminal B, through'contact 5 of relay 1TR,conductor 6, back point of contact 7 of relay ASR, contacts 35 and 36 ofrelay ASPR and time element device TE, respectively, and the winding ofrelay TSR in multiple with a resistor 1r, to terminal N. Relay TSR, uponbecoming energized, will complete its stick circuit, which is the sameas the pickup circuit just traced except that it includes contact 37 ofrelay TSR instead of contacts 35 and 36 of relay ASPR and time elementdevice TE, respectively. With relay TSR energized, relay ASR will becomeenergized promptly by its second pickup circuit, passing from terminalB, through contact 5 of relay 1TR, contacts 8, 10 and 11 of relays TSR,IE8 and XTR, respectively, and the winding of relay ASR to terminal N.Relay ASR, upon becoming" energized, will then complete its stickcircuit previously traced. With relay ASR energized, relay ASPR willbecome energized by its circuit previously traced. Contact 24 of relayASPR will then again be closed in the circuit traced for relay XR, butrelay XR will remain deenergized on account of contact 23 of relay XTRstill being open.

Since relay ASR becomes energized promptly, by the closing of contact 3of relay TSR, when the train leaves section 1T, relay TSR will in turnbecome deenergized quickly by the opening of contact 7 of relay ASR atits back point, and therefore time element device TE will not have timeto close its contact 9. Relay ASR will then remain energized by itsstick circuit. 1

When the train leaves section XT, the pickup and first stick circuitspreviously traced for relay 1ES will become opened at contact 31 ofrelay XTR, but relay 1ES will then remain energized by its second stickcircuit, previously traced. With relays ASR and XTR again energized,relay ICS will become energized by its pickup circuit previously traced.With relay XTR again energized, relay XR will now become energized by acircuit which is the same as the circuit previously traced for thisrelay except that it includes contact 21 of relay lES instead of contact22 of relay 208 which is now open. With relay XR again energized,contact 27 of relay XR will open the circuit for relay FR, causing relayPR to be deenergized, and contact 28 of relay XR will open the lightingcircuits for signal XS, causing lamps 1e and 2e to be extinguished.

When the train leaves section 2T, relay 2C5 will again become energizedby its pickup circuit previously traced, and all parts of the apparatuswill then again be in the normal condition.

I shall next assume that, again an eastbound train has moved oversection 1T and occupies section XT after leaving section IT, and that asecond eastbound train then enters section 1T just before the firsteastbound train leaves section XT. Relay ASR will then becomedeenergized in response to occupancy of section IT by the secondeastbound train, and relay ASPR will become deenergized as before, butwill not release its front contacts until the lapse of a period of timedetermined by capacitor 2 and resistor r in multiple with the Winding ofrelay ASPR. It follows that operation of the crossing signal XS inresponse to the second train will be delayed until the second train hasarrived at some starting oint on section 1T, after the lapse of theperiod of time determined by capacitor t andresistor r, and thereforethere will not be.

has not yet entered. section XT, relay 1ES has not yet become energized.Relay ASR will therefore not become energized by its second pickupcircuit, previously traced. When relay ASPR releases .its contacts,opera t'ion of the crossing signal XS will be started, as previouslydescribed. With relays ASR and ASPR deenergized, the pickup circuit forrelay TSR will become closed as previously traced. Relay TSR, uponbecoming energized, will complete its stick circuit which includescontact 37 of relay TSR instead of contacts 35 and 36 of relay ASPR andtime element device TE, respectively. Time element device TE will thenbecome energized by its circuit passing from terminal B, through contact38 of relay TSR, and the control element 39 of time element device TE toterminal N. The momentary loss of shunt will have ended before timeelement device TE has had time to close its contact 9, and thereforerelay ASR will not become energized during the period of the momentaryloss of shunt. With contact 5 of relay lTR again open at the end of theperiod of the momentary loss of shunt, relay TSR will again bedeenergized, causing the time element device TE to in turn also bedeenergized. Since relay ASR remains deenergized, relays 1C5 and ASPRwill also remain deenergized, and so relay XR will not become energizedduring the period of the momentary loss of shunt. Signal XS willtherefore continue to provide a warning indication to users of thehighway, without interruption because of a momentary loss of shunt oftrack section IT.

I shall next assume that all parts of the apparatus are again, returnedto the normal condition, and that again an eastbound train enterssection 1T, causing relay ASR to be deenergized. I shall assume furtherthat a momentary loss of shunt for the track circuit of section 1Toccurs after relay ASPR has released its contacts. Therefore, with thesecond pickup circuit for relay ASR open at contact of relay 1138, aspreviously described, so that relay ASR is maintained deenergized, relayTSR will become energized, as previously described, by its pickup andstick circuits, and time element device TE will then also becomeenergized, but before time element device T has had time to close itsfront contact 9, any momentary loss of shunt will have ended, so thatagain contact 5 of relay 1TR will open the circuits for relay TSR, andtime element device TE will then again be deenergized. Relays ASR, ASPR,and lCS therefore remain deenergized, and relay XR in turn also remainsdeenergized, so that signal XS will be operated without interruptionbecause of the momentary loss of shunt.

I shall assume still further that a second momentary loss of shuntoccurs a brief period of time after the first momentary loss of shunthas ended, while the eastbound train is still on section IT and beforeit has entered section XT. If contact 36 of time element device TE hasbeen opened because of the energization of device TE during the firstmomentary loss of shunt, and if the second momentary loss of shunt hasoccurred before contact 36 of device TE has had time to close afterdevice TE became'deenergized, relay TSR will not become closed at oncewhen the second momentary loss of shunt occurs. As soon, however, ascontact 36 of device TE becomes closed, relay TSR will become energizedby its pickup and stick circuits previously traced.

It follows that, since contact 36 of time element device TE is includedin the pickup circuit for relay TSR, apparatus embodying my invention,as shown in the accompany ing drawing, provides full protection againstrepeated momentary losses of shunt of the track circuit for section 11,by insuring that time element device TE has been restored to its normalcondition after each such momentary loss of shunt, before the pickuptime for contact 9 of device TE can begin during the next succeedingmomentary loss of shunt.

'I shall now assume that all parts of the apparatus are again in thenormal condition, and that a westbound train enters section 2T,deenergizing relay ZTR. Relay ZCS will then become deenergized becauseof the opening of n act-18 of relay ZTR in th p ck P and Stick r uitfOr'reIa'yZCS. Relay ZCS, upon becoming deenergized, will open, at itscontact 22, the energizing circuit for relay XR, causing relay XR to bedeenergized, which in turn causes signal XS to display a Warningindication to users of the highway.

When the train enters section XT, deenergizing relay XTR, the circuitfor relay XR will again be opened at contact 23 of relay XTR forretaining relay XR deenergized until the train has left section XT. Withrelay 2CS deenergized, and relay XTR deenergized, relay ZWS will becomeenergized by its pickup circuit passing from terminal B, through theback point of contact 32 of relay ZCS, contact 31 of relay XTR, frontpoint of contact of relay ICS, contact of relay IE8, and the winding ofrelay 2W8 to terminal N. Relay 2W8, upon becoming energized, willcomplete a first stick circuit which is the same as the pickup circuitjust traced except that it includes contact 41 of relay ZWS instead ofcontacts 30 and 40 of relays 10S and IE8, respectively.

When the train enters section 1T, relay ASR will become deenergizedbecause of the opening of contact 5 of relay 1TR. Relays ASPR and 1C8will then become deenergized on account of the opening of contacts 14and 15, respectively, of relay ASR. With relay 1CS deenergized, a secondstick circuit will now be completed for relay ZWS, passing from terminalB, through the back point of contact 30 of relay 1CS, contact 41 ofrelay ZWS, and the winding of relay 2WS to terminal N.

When the train leaves section XT, relay 2C8 will again become energizedby its pickup circuit previously traced. With relays ZCSv and 2 WS nowenergized, relay XR will become energized by a circuit passing fromterminal B, through contact 22 of relay 2C5, contact 23 of relay XTR,contact 26 of relay ZWS, and the winding of relay XR to terminal N. Withrelay XR again energized, the operation of signal XS will bediscontinued as previously described.

When the train leaves section 1T, relay ASR will become energizedpromptly by its third pickup circuit, passing from terminal B, throughcontact 5 of relay lTR, conductors 6 and 12, contact 13 of relay ZWS,and the winding of relay ASR to terminal N. With relay ASR againenergized promptly after the train leaves section 1T, relay TSR willbecome deenergized after a brief period of time, thereby avoidingunnecessary operation of time element device TE. With relay ASR againenergized promptly when the train leaves section 1T, relay ASPR will inturn also be energized promptly so that if the train should now reverseits movement and again enter section 1T, the operation of the crossingsignal will be delayed, as previously described, until the train hasarrived at some starting point in section IT as determined by resistor rand capacitor 2 in multiple with relay ASPR.

If, after all parts of the apparatus have again been restored to thenormal condition, there should be a momentary shunting of the trackcircuit, or other momentary failure of the track circuit for section 1T,relay ASR will become deenergized because of the opening of contact 5 ofrelay ITR, and then when contact 5 of relay lTR again becomes closed,relay TSR would become energized as previously described, causing timeelement device TE to become energized. Upon the lapse of a measuredperiod of time, the first pickup circuit traced for relay ASR wouldbecome closed by contact 9 of time element device TE, this circuitpassing from terminal B, through contact 5 of relay iTR, contact 8 ofrelay TSR, contact 9 of time element device TE, and the winding of relayASR to terminal N. It follows that with apparatus embodying myinvention, as shown in the accompanying drawing, if there should be amomentary failure of a track circuit for section 1T, the parts of theapparatus would be automatically restored to the normal condition whencontact 5 of relay ITR again becomes closed.

Although -I have shown apparatus embodying my invention for a stretch ofrailway track over which tralfic movements are normally made in bothdirections, it is believed to be obvious to persons familiar with therailway signaling art that my invention could also be used for a stretchof railway track over which traffic movements are normally made in onlyone direction. It is also belie'ved to be obvious to persons familiarwith the railway signaling art that certainportions such, for example,as one of the directional stick relays IE8 and ZWS of the apparatusshown in the accompanying drawing could be omitted if my invention wereused for a stretch of railway track over which traffic movements arenormally made in only one direction. It is believed to be furtherobvious to persons skilled in railway signaling that various operablecombinations such as recited in the attached claims could be provided ifother portions of the apparatus shown in the accompanying drawing wereomitted.

I have described the operation of the apparatus, shown in theaccompanying drawing, under a few typical sets of conditions. It isbelieved that, in view of the foregoing description, the operation ofthe apparatus can be readily traced for any other possible set ofconditions.

Although I have herein shown and described only one form of apparatusembodying my invention, it is understood that various changes andmodifications may be made therein within the scope of the appendedclaims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In a control system for a highway crossing signal adjacent theintersection of a highway with a railway track which is divided into acrossing section including the intersection and a first approach controlsection adjacent one end of said crossing section and also a secondapproach control section adjacent the opposite end of said crossingsection, each of said sections being provided with a track circuitincluding a source of current and a track relay which is normallyenergized but which becomes deenergized in response to occupancy of thecorresponding section by a train, the combination comprising, anapproach stick relay, a timing stick relay, a time element device havinga front contact which is open while said device is deenergized but whichbecomes closed when said device has been energized a measured period oftime, said time element device having also a back contact which becomesopened in response to energization of said time element device and whichagain becomes closed upon the lapse of a second measured period of timeafter said time element device becomes deenergized, means including afront contact of said timing stick relay for controlling energization ofsaid time element device, a repeater relay, a control circuit for saidrepeater relay controlled by a front contact of said approach stickrelay and including a capacitor and a resistor connected in series witheach other in a path in multiple with the winding of said repeaterrelay, a pickup and a stick circuit for said timing stick relay eachcontrolled by a front contact of the track relay for said first approachcontrol section and by a back contact of said approach stick relay andsaid pickup circuit also controlled by a back contact of said repeaterrelay and by said back contact of said time element device, a first anda second control stick relay each having a pickup circuit controlled bya front contact of the track relay for said crossing section, the pickupcircuit and a stick circuit for said first control stick relay alsocontrolled by a front contact of said approach stick relay, the pickupand a stick circuit for said second control stick relay also controlledby a front contact of the track relay for said second approach controlsection, a first directional relay controlled by back contacts of saidfirst control stick relay and the track relay for said crossing section,a second directional relay controlled by back contacts of said secondcontrol stick relay and the track relay for said crossing section, afirst and a seond and a third pickup circuit and also a stick circuitfor said approach stick relay each controlled by a front contact of thetrack relay for said first approach control section, said first andsecond pickup circuits also controlled by a front contact of saidtimingstick relay, said'firsfpickup circuit also controlled by saidfront contact of said time element device, said second pickup circuitalso controlled by a front contact of said first directional relay andby a back contact of the track relay for said crossing section, saidthird pickup circuit also controlled by a front contact of said seconddirectional relay, a crossing signal 0on trol relay controlled by afront contact of the track relay for said crossing section and by afront contact of said second control stick relay in multiple with afront contact of said first directional relay and also by a frontcontact of said first control stick relay in multiple with a frontcontact of said repeater relay and with a front contact of said seconddirectional relay, and means controlled by a back contact of saidcrossing signal control relay for controlling said highway crossingsignal.

2. In a control system for .a highway crossing signal adjacent theintersection of a highway with .a railway track which is divided into acrossing section including the intersection and a first approach controlsection adjacent one end of said crossing section and also a secondapproach control section adjacent the opposite end of said crossingsection, each of said sections being provided with a track circuitincluding a source of current and a track relay which is normallyenergized but which becomes deenergized in response to occupancy of thecorresponding section by a train, the combination comprising, anapproach stick relay, a timing stick relay, 2. time 1 element devicehaving a front contact which is open while said device is deenergizedbut which becomes closed when said device has been energized a measuredperiod of time, said time element device having also a back contactwhich becomes opened in response to energization of said time elementdevice and which again becomes closed upon the lapse of a secondmeasured period of time after said time element device becomesdeenergized, means including a front contact of .said timing stick relayfor controlling energization of said time element device, a repeaterrelay, a control circuit for said repeater relay controlled by a frontcontact of said approach stick relay and including a capacitor and aresistor connected in series with each other in a path in. multiple withthe winding of said repeater relay, a pickup and'a stick circuit forsaid timing stick relay each controlled by a front contact of the trackrelay for said first approach control section and by a back contact ofsaid approach stick relay and said pickup circuit also controlled by aback contact of said repeater relay and by said back contact of saidtime element device, a first directional relay controlled by the trackrelays for said first approach control section and said crossing sectionto become energized when a train on said first approach control sectionapproaching said intersection enters said crossing section, a seconddirectional relay controlled by the track relays for said secondapproach control section and said crossing section to become energizedwhen a train on said second approach control section approaching saidintersection enters said crossing section, a first and a second and athird pickup circuit and also a stick circuit for said approach stickrelay each controlled by a front contact of the track relay for saidfirst approach control section, said first and second pickup circuitsalso controlled by a front contact of said timing stick relay, saidfirst pickup circuit also controlled by said front contact of said timeelement device, said second pickup circuit also controlled by a frontcontact of said first directional relay and by a back contact of thetrack relay for said crossing section, said third pickup circuit alsocontrolled by a frontcontact of said second directional relay, acrossing signal control relay controlled by said track relays and bysaid trafiic directional relays and also by said repeater relay to benormally energized but to become deenergized when a train occupieseither of said approach control sections while approaching saidintersection or whena train occupies said crossing section but to becomeenergizedwhen a. train leaves said crossing section, and

means Controlled by a back contac f. said cros ing signa control relayfor controlling said highway crossing signal,

3. In a control system for a highway crossing signal adjacent theintersection of a highway with a railway track which is divided into acrossing section including the intersection and a first approach controlsection adjacent one end of said crossing section and also a secondapproach control section adjacent the opposite end of said crossingsection, each of said sections being provided with a track circuitincluding a source of current and a track relay which is normally energzed but which becomes deenergized in response to occupancy of the COI-responding section by a train, the combination comprisng, an approachstick relay, a time element device having a. contact which is open whilesaid device is ec crgized but which becomes closed when said device hasbeen energized a measured period of time, a repeater relay, a controlcircuit for said repeater relay controlled by a front contact of saidapproach stick relay and including an en- 'ergy storing device inmultiple with the Winding of said repeater relay, means controlled by afrom contact of the track relay for said first approach control sectionand by back contacts of said approach stick relay and said repeaterrelay for energizing said time element device, a first directional relaycontrolled by the track relays for said first. approach control sectionand said crossing sec tion to become energized when a train enters saidcrossing section from said first approach control section, a seconddirectional relay controlled by the track relays for said secondapproach control section and said crossing section to become energizedwhen a train enters said crossing section from said second approachcontrol section, a first and a second and a third pickup circuit and astick circuit for said approach stick relay cach controlled by a frontcontact of the track relay for said first approach control section, saidfirst pickup circuit also controlled by said contact of said timeelement device, said second pickup circuit also controlled by a frontcontact olf said first directional relay and by :a back contact of thetrack relay for said crossing section, said third pickup circuit alsocontrolled by a front contact of said second directional relay, andmeans controlled by said track relays and by said directional relays andalso by said repeater relay to be normally energized but to becomedeenergized when a train occupies either of said approach controlsections while approaching said intersection or when a train occupiessaid crossing section and to become energized when a train leaves saidcrossing section for control ing said highway crossing signal.

4. In a control system fora highway crossing signal adjacent theintersection of a highway with a stretch of railway track whichcomprises a crossing section including the intersection and a firstapproach control sec? tion adjacent one end of said crossing section andalso a second approach control section adjacent the opposite end of saidcrossing section, each of said sections being provided with tralficmeans which is in a first condition when the corresponding section isunoccupied but which assumes a second condition in response to occupancyof the corresponding section by a train, the combination c mp g, n pp hs i k r ay, me lemen mean a repeater relay, a control circuit for saidrepeater relay controlled by a front contact of said approach stickrelay and including an energy storing device in multiple with theWinding of said repeater relay, means controlled by the traffic meansfor said first approach com-I0 section in its first condition and byback contacts of said approach stick relay and said repeater relay forenergizing said time element means, a first directional relay controlledby the tratfic means for said first approach control section and saidcrossing section to become energized when a train enters said crossingsection from said first approach control section, a second directionalrelay controlled by the trafiic means for said second approach controlsection and said crossing section .to become energized when a trainenters .said crossing section from said second approach control section,a f rst and a second and a third pickup circuit and also a stick circuitfor said approach stick relay each controlled by said traffic means forsaid first approach control section in its first condition, said firstpickup circuit also, controlled by a contact which becomes closed bysaid time element means after said time element means has been energizeda measured period of time, said second pickup circuit also controlled bya front contact of said first directional relay and by the traffic meansfor said crossing section in its second condition, said third pickupcircuit also controlled by a front contact of said second directionalrelay, and means controlled by the trafiic means for said crossingsection in its second condition or by the trafiic means for said secondapproach control section in its second condition while said firstdirectional relay is deenergized or by the trafiic means for said firstapproach control section in its second conditinn while s epe elay a daid e ond dir c ona relay are both deenergized for efiecting operationof said highway crossing signal.

5. In a control system for a highway crossing signal adjacent theintersection of a highway with a stretch of railway track whichcomprises a crossing section including the intersection and an approachcontrol section adjacent one end of said crossing section, each of saidsections being provided with trafiic means which is in a fir ond io whle h o spondin se on i unocpi d ut hich assume a s c nd ti in e ponse occ pa cy oi e c r spon ng s t o y a tra n, the combination comprising,an approach stick relay, time element means, a repeater relay, a controlcircuit fol said repeater relay controlled by a front contact of said ppa h s c re ay a d uding an e e y storing device in multiple with thewinding of said repeater relay, means controlled by the traflic meansfor said approach control section in its first condition and by backconacts f s id appr c stick lay and s r p e e ay for energizing saidtime element means, a directional relay controlled by the trafiic meansfor said approach control section and said crossing section to becomeenergized when a train enters said crossing section from said approachcontrol section, a first and a second pickup circuit and also a stickcircuit for said approach stick l y ac control d y said trafi c m ans os d appr h. nt o sec on n. i firs c n it on, a d fi s pi kup circuitalso con ro l y a co ac wh ch ecomes clos d by said me cl m n m s h saide men me n h be ner zed a m su d p od Of me, aid ond P ck p c rcui s conrol e by a front contact of said directional relay and by the trafc e nf r said ros ng ct n n it s c nd. condition, and means controlled by thetraffic means for said crossing section in its second condition or bythe trafiic means for said approach control section in its secondcondition while said repeater relay is deenergized for eflectingoperation of said highway crossing signal.

6. In a control system for a highway crossing signal adjacent theintersection of a highway with a stretch of railway track whichcomprises a crossing section includ-v ing he nter ct on an n approach crol s c ion djacent one end of said crossing section, each of saidsections being provided with traffic means which is in a first conditionwhile the corresponding section is unoccupied but which assumes a secondcondition in response to occupancy of the corresponding section by atrain, the combination comprising, an approach stick relay, time clementmeans, a r peat r rc ay, a n r l circuit for a d repeater r lay c ntolled y a front con act f id ap p e ch sti k relay and in lud ng an n gyring d i in multiple with the winding of said repeater relay, a timingstick relay, a p ck p and a ti k circ i fo a d tim g tick relay ea h c nr l ed y th r fiic m an f r sai appr a h co trol s t on n it fir conditon,

said pickup circuit also controlled by a back contact of said repeaterrelay, means controlled by a front contact of said timing stick relayfor energizing said time element means, a directional relay controlledby the traffic means for said approach control section and said crossingsection to become energized when a train enters said crossing sectionfrom said approach control section, a first and a second pickup circuitand also a stick circuit for said approach stick relay each controlledby said traflic means for said approach control section in its firstcondition, each of said pickup circuits also controlled by a frontcontact of said timing stick relay, said first pickup circuit alsocontrolled by a contact which becomes closed by said time element meanswhen said time element means has been energized a measured period oftime, said second pickup circuit also controlled by a front contact ofsaid directional relay and by the traffic means for said crossingsection in its second condition, and means controlled by the trafficmeans for said crossing section in its second condition or by thetrafiic means for said approach control section in its second conditionwhile said repeater relay is deenergized for eifecting operation of saidhighway crossing signal.

7. In a control system for a highway crossing signal adjacent theintersection of a highway with a stretch of railway track whichcomprises a crossing section including the intersection and an approachcontrol section adjacent one end of said crossing section, each of saidsections being provided with trafi'lc means which is in a firstcondition while the corresponding section is unoccupied but whichassumes a second condition in response to occupancy of the correspondingsection by a train, the combination comprising, an approach stick relay,time element means, a repeater relay, a control circuit for saidrepeater relay controlled by a front contact of said approach stickrelay and including an energy storing device in multiple with thewinding of said repeater relay, means controlled by the, trafiic meansfor said approach control section in its first condition and by a backcontact of said repeater relay for energizing said time element means, adirectional relay controlled by the traffic means for said approachcontrol section and said crossing section to become energized when atrain enters said crossing section from said approach control section, afirst and a second pickup circuit and also a stick circuit for saidapproach stick relay each controlled by said traffic means for saidapproach control section in its first condition, said first pickupcircuit also controlled by a contact which becomes closed by said timeelement means when said time element means has been energized a measuredperiod of time, said second pickup circuit also controlled by a frontcontact of said directional relay, and means controlled by the trafficmeans for said crossing section in its second condition or by thetrafiic means for said approach control section in its second conditionwhile said repeater relay is deenergized for eifecting operation of saidhighway crossing signal.

8. In a control system for a highway crossing signal adjacent theintersection of a highway with a stretch of railway track whichcomprises a crossing section including the intersection and an approachcontrol section adjacent one end of said crossing section, each of saidsections being provided with traffic means which is in a first conditionwhile the corresponding section is unoccupied but which assumes a secondcondition in response to occupancy of the corresponding section by atrain, the combination comprising, an approach stick relay, time elementmeans, a repeater relay, a control circuit for said repeater relaycontrolled by a front contact of said approach stick relay and includingan energy storing device in multiple with the winding of said repeaterrelay, means controlled by the traffic means for said approach controlsection in its first condition and by a back contact of said repeaterrelay for energizing said time element means, a first and a secondpickup circuit and also a stick circuit for said approach stick relayeach controlled by said trafiic means for said approach control sectionin its first condition, said first pickup circuit also controlled by acontact which becomes closed by said time element means when said timeelement means has been energized a measured period of time, said secondpickup circuit also controlled by said trafiic means for said crossingsection in its second condition, and means controlled by the traflicmeans for said crossing section in its second condition or by thetraffic means for said approach control section in its second conditionif said repeater relay is deenergized for effecting operation of saidhighway crossing signal.

9. In a control system for a highway crossing signal adjacent anintersection of a highway with a stretch of railway track, incombination, crossing signal control means, slow release relay means foractuating said crossing signal control means, an approach stick relay, atiming stick relay, a time delay device, a track circuit including atrack relay located on said stretch a predetermined distance from saidintersection, said approach stick relay having a pickup circuitcontrolled by a front contact of said track relay and front contacts ofsaid timing stick relay and said time delay device, and a stick circuitcontrolled by said front contact of said track relay, a pickup circuitfor said slow release means controlled by a front contact of saidapproach stick relay, said timing stick relay having a pickup circuitcontrolled by back contacts of said approach stick relay, said slowrelease relay means and said time delay device and said front contact ofsaid track relay, a stick circuit for said timing stick relay shuntingsaid back contacts of said slow release relay means and said time delaymeans, and a pickup circuit for said time delay means controlled by afront contact of said timing stick relay.

References Cited in the file of this patent UNITED- STATES PATENTS2,209,225 Evans et a1. July 23, 1940 2,346,518 Tizzard Apr. 11, 19442,677,047 Mishelevich Apr. 27, 1954 2,684,435 Haines June 20, 1954

